Add fake llm provider

Change-Id: I7983796013f27e146506a42c8238b69a1838f1d9
diff --git a/server/llm/llm.go b/server/llm/llm.go
index 2fd3bf3..aa63c3e 100644
--- a/server/llm/llm.go
+++ b/server/llm/llm.go
@@ -35,6 +35,7 @@
 	ProviderClaude Provider = "claude"
 	ProviderGemini Provider = "gemini"
 	ProviderLocal  Provider = "local"
+	ProviderFake   Provider = "fake"
 )
 
 // Role represents the role of a message participant
@@ -270,4 +271,10 @@
 		Timeout:    60 * time.Second,
 		MaxRetries: 1,
 	},
+	ProviderFake: {
+		Provider:   ProviderFake,
+		BaseURL:    "fake://test",
+		Timeout:    1 * time.Second,
+		MaxRetries: 0,
+	},
 }